Amongst the cooled components used in blast furnaces are the coolers, such as stack and bosh coolers, which are built into the refractory lining of the furnace, and tuyeres. These components are normally castings of copper or copper alloy.
The noses of tuyeres and coolers inevitably become exposed to erosion by the burden of ore, coke, limestone, etc., in the blast furnace, the exposure becoming progressively greater as the furnace lining wears away.